1. Field of the Invention
The present invention relates to a composite material having a substantially sandwich-like structure. This sandwich structure comprises two layers formed by threads mutually connected by pile threads.
2. Description of the Prior Art
A known composite material comprises two layers in the form of web layers, while the pile threads couple the two web layers. A composite material based on a three-dimensional web has the drawback, however, that the layers are substantially vapour and/or moisture-proof and are therefore unsuitable for use in contact with the human/animal body. In addition the use of web layers has the drawback when one or both of the web layers is provided with a matrix, that a closed layer is created which is not moisture/vapour-permeable. While it is the case that a composite material based on three-dimensional webs is vapour/moisture-permeable, it is insufficiently strong and rigid. This could be improved by covering knitted layers with flat strengthening materials, whereby they become impermeable. Kunststoffe, vol. 80, no. 9, September 1990, pages 1003-1007 discloses a composite comprising an additional covering layer for the provision of sufficient strength to a sandwich structure.